Genotoxic Responses of Mitochondrial Oxygen Consumption Rate and Mitochondrial Semiquinone Radicals in Tumor Cells
Genotoxic Responses of Mitochondrial Oxygen Consumption Rate and Mitochondrial Semiquinone Radicals in Tumor Cells
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肿瘤细胞线粒体耗氧率和线粒体半醌自由基的基因毒性反应
DOI：
10.1007/s00723-018-1007-0
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发表时间：
2018
影响因子：
1
通讯作者：
Inanami Osamu
中科院分区：
文献类型：
--
作者：
Yamamoto Kumiko;Yasui Hironobu;Bo Tomoki;Yamamori Tohru;Hiraoka Wakako;Yamasaki Toshihide;Yamada Ken-ichi;Inanami Osamu
我们最近的报告表明，遗传毒性刺激增强线粒体能量代谢在各种肿瘤细胞系。然而，线粒体对遗传毒性刺激的反应尚未完全阐明。为了研究X射线照射后细胞线粒体的功能，采用电子自旋共振（ESR）技术研究了5，9，14，18，2,3，27，32，36-八正丁氧基-2，3-萘嵌锂对人宫颈腺癌HeLa细胞氧耗率（OCR）的影响。ESR血氧测定表明，基础呼吸，ATP相关呼吸，质子漏，最大呼吸，并在HeLa细胞增加X射线照射后24小时储备能力。然而，使用MitoTracker绿色的流式细胞术分析显示，X射线照射后线粒体质量也增加。当OCR标准化的线粒体膜质量，辐射诱导的呼吸参数的增加消失。这一发现表明，辐射诱导的细胞OCR增加的线粒体质量的增加，但不是通过激活的线粒体相关酶的解释。此外，线粒体半醌自由基atg= 2.004检测低温（110 K）ESR波谱。半醌自由基的ESR信号强度增强X-照射，这表明在电子传递链中的电子流的增加。这些数据对于理解靶向放射增敏剂在肿瘤细胞中的放射增敏机制具有重要意义。
Our recent report demonstrated that genotoxic stimuli enhance mitochondrial energy metabolism in various tumor cell lines. However, the mitochondrial response against genotoxic stimuli has not been fully elucidated. In this study, to investigate mitochondrial functions in X-irradiated cells, the oxygen consumption rate (OCR) in human cervical adenocarcinoma HeLa cells was examined by electron spin resonance (ESR) spectroscopy with lithium 5,9,14,18,23,27,32,36-octa-n-butoxy-2,3-naphthalocyanine. ESR oximetry demonstrated that basal respiration, ATP-linked respiration, proton leak, maximal respiration, and reserve capacity increased in HeLa cells 24 h after X-irradiation. However, a flow cytometric analysis using MitoTracker Green showed that mitochondrial mass also increased following X-irradiation. When the OCR was standardized to the mitochondria membrane mass, the radiation-induced increases in the respiratory parameters disappeared. This finding indicated that the radiation-induced increase in cellular OCR was explained by an increase in mitochondrial mass but not by the activation of mitochondrial respiratory-related enzymes. In addition, mitochondrial semiquinone radicals atg= 2.004 were detected by low-temperature (110 K) ESR spectroscopy. The ESR signal intensity of semiquinone radicals was enhanced by X-irradiation, suggesting an increase in the electron flow in the electron transport chain. These data will be important to understand the mechanism of radio-sensitization by mitochondria-targeting reagents in tumor cells.